Researchers at Tel Aviv University in Israel assessed daily cannabis use in 47 Parkinson’s patients over several months.

A grand majority – 82 percent – said cannabis “improved their overall symptoms.” These patients experienced reductions in pain, stiffness and tremors. They also reported enhanced mood and sleep quality, as well as fewer falls. (click!)

This sounds great – you practically get a contact high reading it – if it weren’t for so many caveats:

The quantity of marijuana that each participant consumed varied, as did the form of delivery: 80% of the participants smoked marijuana cigarettes.

The data were collected via telephone interviews in which the participants spoke retrospectively and subjectively about what they had experienced. Retrospective self-reporting is often not reliable.

Who really knows what part of marijuana’s complex makeup is responsible for producing these good results? According to Wikipedia, “Cannabis contains more than 460 compounds, at least 80 of these are cannabinoids – chemical compounds that interact with cannabinoid receptors in the brain. As of 2012, more than 20 cannabinoids were being studied by the U.S. FDA.” If you live in a country or one of the states in the USA where medical marijuana is both legal and quality-controlled, you may be in luck with your purchase. But for everyone else: does the pot you buy from your former grad school roommate’s cousin contain the right blend of chemical ingredients?

The research reported in the three articles is anecdotal. Again, according to Wikipedia, “Anecdotal evidence and pre-clinical research has suggested that cannabis or cannabinoids may be beneficial for treating Huntington’s disease or Parkinson’s disease, but follow-up studies of people with these conditions have not produced good evidence of therapeutic potential.”

No placebo control, blinding or randomization, nor confidence intervals for the purported benefits

Patients with Parkinson disease (PD) are uniquely susceptible to the placebo effect due to the role of dopamine in expectation effects. Studies which do not include placebo control, double-blinding and randomization of subjects to therapy, cannot claim to provide more than anecdotal data.

Medical cannabis has been legalized in many states, but remains on Schedule 1 as an illegal drug at the national level. Because the commercial cultivation of cannabis is also illegal, most is supplied by underworld criminal sources. High levels of herbicides such as paraquat have been measured in marijuana, exposure to which is a risk factor for PD. I would insist on cannabis grown under safe legal conditions before risking exposure of PD patients to unknown levels of herbicides.

It is difficult to imagine how an intoxicant like cannabis, which impairs so many neurological functions, could reduce falls in PD patients. PD patients are also susceptible to dementia, and the long-term dementia risk of cannabis intoxication is not known.

As a clinician, I cannot at this time place any credence in these reported benefits of cannabis for the treatment of PD.

But then, on the flip side, you have all these YouTube videos that show astonishing outcomes. For example:

We live in a time of uncertainty, and here’s another example of it. Because research into the medical benefits of marijuana is to a great extent blocked in many countries, including the USA, the acceptance and approval of marijuana by everyone in the Parkinson’s medical community may forever be in the offing.

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